Along with the development of Internet services and the application of broadband access networks and radio networks, extensive attention is paid to the fast and convenient access networks. Meanwhile, researches on combining advantages of a mobile access network with advantages of a fixed access network are becoming a new focus of the communication industry for a better utilization of the existing network resources and a better control of the costs for the operators of network devices.
FIG. 1 is a schematic diagram illustrating a conventional Universal Mobile Telecommunications System (UMTS) network. The network includes a Mobile Station (MS), a Radio Network Controller (RNC), a base station (Node B) and various network devices.
The MS which is a user terminal device of the UMTS has such functions as radio measuring, service establishing, packet receiving/transmitting and mobility managing. The RNC and the NodeB which provide the MS with the radio access resource have such functions as radio access controlling, air interface accessing of data and voice, radio resource managing and mobility managing. Network devices of the system include a Mobile Switched Center/Visit Location Register (MSC/VLR), a Home Location Register (HLR), a Gateway Mobile Switched Center (GMSC), a General Packet Radio Service (GPRS), a Gateway GPRS Support Node (GGSN), a Service GPRS Supporting Node (SGSN) and etc. The network devices of the system have such functions as network access controlling, packet routing and forwarding, mobility managing and network managing.
FIG. 2 is a schematic diagram illustrating the structure of a conventional radio communication system. With reference to FIG. 2, in the conventional radio communication system, an Access Point (AP) which implements the function of a Node B connects to the RNC via an interface between the RNC and the Node B (IUB) interface. Upon concentrating a great number of APs, the RNC connects to such a core network device of a Circuit Switched (CS) domain as a Mobile Switched Center (MSC) via an IU-CS interface, and connects to such a core network device of a Packet Switched (PS) domain as an SGSN and a GGSN via an IU-PS interface.
The following disadvantages are found during accessing the network with the system as shown in FIG. 2. Both the Internet service and the service operating in the service platform provided by operators need to forward service between the RNC and the Internet or between the RNC and the service platform provided by operators via a GGSN and an Access Gateway (AG) which has the function of an SGSN, which leads to a large processing load of the AG and the GGSN. The Internet service and the service operating in the service platform provided by operators both belong to PS services. The Internet service refers to a WEB service which may be accessed through the PS. The service operated in the service platform provided by operators refers to a service providing a high increment value for operators, and the service is controlled and managed by operators.
A great number of APs concentrate at the RNC and all service traffic of the APs needs to pass through the RNC, and the RNC also needs to process air interface protocol stacks. Therefore, the RNC has an excessive processing load and a limited number of APs can be administrated.
In addition, in the conventional network architecture, a Frame Protocol (FP) which requires a higher Quality of Service (QOS) is used as a transfer protocol in the IUB interface between the AP and the RNC. A home wideband service which provides a lower QOS is used as an IP transfer mode between the AP and the RNC, and the IP transfer mode may lead to an abnormal operation of the FP protocol in an extreme situation.
In other networks, such as a GPRS network, a Code Division Multiple Access (CDMA) 2000 network and a Time Division-Synchronous-Code Division Multiple Access (TD-SCDMA) network, a similar problem also exists.